A dual mass flywheel (hereinafter referred to as a flywheel) is generally used for damping a torsional vibration that is generated during power transmission between an output shaft of an engine and an input shaft of a transmission. Typical prior flywheels include a first mass, a second mass, and a damping unit disposed between the first and second masses. The first mass is connected to the output shaft of the engine, and the second mass is connected to the input shaft of the transmission through a clutch mechanism.
The first and second masses are connected to each other through the damping unit such that the first and second masses can rotate relative to each other. Generally, the engine drives wheels, but the engine may be driven by an inertia force of a vehicle. Therefore, the first and second masses must be designed to relatively rotate in both directions.
When engine torque is substantially high and the vehicle is driven with a specific gear ratio, a relative rotation between the first and second masses reaches its limit. Furthermore, when the engine torque changes irregularly, the first and second masses may be dashed against a member for limiting the relative rotation of the first and second masses.
To solve such problems, the flywheel is designed to have a high level of damping characteristics.
In the prior flywheel, when the relative rotation between the first and second masses occurs, a magnitude of torque cannot be regulated. Furthermore, a damping effect of the flywheel is almost constant even when the relative rotation between the first and second masses occurs. The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.